Expression of Vascular Endothelial Growth Factor and Presence of Angiovascular Cells in Tissues from Different Thyroid Disorders

Background

Vascular endothelial growth factor (VEGF) is involved in tumor angiogenesis and other pathophysiological processes.

Materials and methods

We studied the localization of VEGF in human thyroid tissues to clarify its involvement in proliferative processes in a variety of thyroid disorders. Immunohistochemical analysis using purified rabbit polyclonal anti-human VEGF or anti-human CD34 antibody and a streptavidin–biotin peroxidase complex detection system was performed on 58 tissue specimens from 53 patients with different thyroid disorders and 5 normal thyroid glands.

Results

Vascular endothelial growth factor was not detected in normal thyroid follicular cells. However, some thyroid tumor cells expressed VEGF in the cytoplasm (papillary carcinoma, 10/18; follicular carcinoma, 1/3; medullary carcinoma, 2/2; follicular adenoma, 3/11; adenomatous goiter, 2/4). In benign follicular adenoma and adenomatous goiter, weak expression of VEGF was found in small areas of the tumor, whereas in malignant thyroid tumors, it was strongly expressed in many cells. However, VEGF was not expressed in anaplastic carcinoma, malignant lymphoma, or Graves’ disease. Angiovascular cells stained with CD34 antibody in tissues from different thyroid disorders reflected statistically significant differences in papillary carcinoma, follicular adenoma, and Graves’ disease compared with normal thyroids, and such cells showed a trend toward increases in medullary carcinoma and adenomatous goiter. In contrast, low vascularity was observed in anaplastic carcinoma, malignant lymphoma, and follicular carcinoma.

Conclusions

Because VEGF probably functions as a hypoxia-inducible angiogenic factor, overexpression of this mediator, concomitant with hypervascularity, may be induced more strongly in malignant thyroid tumors, which need more oxygen to proliferate, than in benign follicular tumors. However, neither VEGF nor CD34 was expressed in anaplastic thyroid carcinoma, which is an extremely poorly differentiated malignant tumor. CD34 but not VEGF was expressed in the hyperplastic thyroid tissues of Graves’ disease composed of nontransformed cells. Thus, the expression of VEGF concomitant with CD34 is suggested to reflect both the transformation and differentiation state of malignant tumors.     

Classification, staging, prognostic factors and risk factors in thyroid carcinoma

Thyroid carcinomas arise from follicular cells (papillary, follicular, Hurthle, anaplastic), parafollicular cells (medullary) and stroma (lymphoma, sarcoma). Gradation and prognostic factors are different for every one of histological type. Most patients with papillary and follicular thyroid cancer have an excellent prognosis. At the other extreme is anaplastic thyroid cancer whose usual mean survival can be measured in months. Exposure to external radiation and living in endemic goiter area increase the frequency of thyroid cancer. Medullary thyroid carcinoma is often familial and may occur in associations with the multiple endocrine neoplasia syndromes.     

The grooved nucleus. A useful diagnostic criterion of papillary carcinoma of the thyroid

The optically clear nucleus has been recognized widely as an important histological feature of papillary carcinoma of the thyroid, and it is now considered by many workers as standing on an equal basis with the papillae for the diagnosis of this tumor. However, clear nuclei are sometimes patchy in distribution or absent in papillary carcinoma, and may be difficult to differentiate from pseudoclear nuclei which may be found in a variety of thyroid lesions. This study was undertaken to determine whether the grooving of the nuclei, a well-recognized electron-microscopic feature, can serve as an additional reliable light microscopic diagnostic criterion of papillary carcinoma. The histological sections of 103 consecutive cases of thyroid carcinoma, (including 89 cases of papillary carcinoma), 100 consecutive noncancer thyroidectomy specimens, and five cases of Hashimoto's thyroiditis were reviewed. Grooved nuclei were found in all cases of papillary carcinoma in almost every high-power microscopic field, and in the two cases of poorly differentiated thyroid carcinoma. Similar nuclei were found in only a very occasional field in four cases of adenoma, and one case each of multinodular goiter and Hashimoto's thyroiditis. We conclude that the deep grooving of the nuclei is a useful cytological feature for the diagnosis of papillary thyroid carcinoma.     

CD10表达在甲状腺滤泡性癌和滤泡型乳头状癌诊断中的作用

目的研究CD10表达在甲状腺滤泡性癌和滤泡型乳头状癌诊断中的作用。方法收集70例甲状腺良、恶性病变组织，其中包括15例滤泡性腺瘤、15例腺瘤性甲状腺肿、30例乳头状癌（包括9例滤泡型乳头状癌）和10例滤泡性癌，采用免疫组织化学方法检测CD10在上述组织中的表达。结果9例滤泡型乳头状癌中，7例表达CD10（77．8％），10例滤泡性癌中8例表达CD10（80．0％）；CD10在非滤泡型乳头状癌、滤泡性腺瘤、腺瘤性甲状腺肿和正常甲状腺组织中均不表达。结论对CD10表达的检测有助于对甲状腺滤泡性癌和滤泡型乳头状癌的诊断。     

CD10在甲状腺疾病中的表达及意义

目的研究CD10在甲状腺疾病中的表达及意义。方法收集70例甲状腺良、恶性病变组织,其中15例滤泡性腺瘤、15例腺瘤性甲状腺肿、30例乳头状癌和10例滤泡性癌。采用免疫组织化学的方法检测CD10在上述病变中的表达。结果9例滤泡型乳头状癌中,7例表达CD10,CD10阳性率为77％。10例滤泡性癌中,8例表达CD10,阳性率为80％。而在滤泡性腺瘤和腺瘤性甲状腺肿及21例普通型乳头状癌组织中CD10均不表达。CD10在滤泡型乳头状癌和滤泡性癌中的阳性率显著高于滤泡性腺瘤和腺瘤性甲状腺肿中的阳性率（P〈0．01）。结论对CD10表达的检测有助于对甲状腺滤泡性癌和滤泡型乳头状癌的诊断。     

The optically clear nucleus. A reliable sign of papillary carcinoma of the thyroid?

The clear ("Orphan Annie Eye") nucleus has been accepted as one of the important microscopic features of papillary carcinoma of the thyroid. This study undertook an examination of 100 consecutive thyroid lesions exclusive of papillary, mixed, and follicular carcinomas for the presence of these nuclei. Only two lesions (2%), a follicular adenoma and diffuse hyperplasia, had such nuclear morphology but as focal changes. Thirty-seven cases of papillary, mixed, and follicular carcinoma were also studied. Clear or empty nuclei were present in 83% of papillary carcinomas. One carcinoma of follicular type had clear nuclei in a diffuse distribution. "Pseudoclear" nuclei were noted in a variety of situations ranging from normal thyroids to diffuse hyperplasia, where they were present in 65% of cases. We conclude that clear nuclei when present as a diffuse changes in a thyroid tumor are a reliable sign of papillary carcinoma but are not pathognomonic. If the character of the clear nuclei is questionable, other histologic features of papillary carcinoma should be looked for, such as papillae with overlapping nuclei, psammoma bodies and multicocality. It was also fould that frozen sections and imprints do not demonstrate the nuclei; they appear only in fixed tissues.     

Measurement of cellular DNA content in thyroid tumors by the flow cytometer

Cellular DNA contents measured by flow cytometer were analysed in relation to histopathological classification and clinicopathological findings in 94 patients with thyroid tumors. The DNA determination was carried out on both tumor tissues and surrounding thyroid tissues. As an indicator of tumor growth, proliferative index (PI) and DNA index were calculated from DNA histograms. The PI value (mean +/- SD) was 32.5 in medullary carcinoma, 31.3 +/- 10.2 in follicular carcinoma, 28.2 +/- 6.2 in papillary carcinoma, 21.6 +/- 4.4 in follicular adenoma, and 20.6 +/- 4.4 in adenomatous goiter, respectively, whereas the value in normal thyroid tissues was 4.1 +/- 2.2. PI values in the surrounding thyroid tissues in cases of follicular and papillary carcinomas were significantly (p less than 0.01) lower than those of the corresponding cancer tissues, but they were higher than that of the normal tissues. The DNA index and frequencies of aneuploidy were 1.15 and 50.0% in medullary carcinoma; 1.25 +/- 0.27 and 66.7% in follicular carcinoma; 1.19 +/- 0.25 and 64.2% in papillary carcinoma; 1.01 +/- 0.04 and 9.3% in follicular adenoma; and 1.00 +/- 0.00% in adenomatous goiter. The result implies that PI value and DNA index are relatively correlated with clinicopathological criteria of malignancy of individual thyroid tumors, and they may become a putative tool for determination of the biological malignancy.     

Encapsulated papillary oncocytic neoplasms of the thyroid: morphologic, immunohistochemical, and molecular analysis of 18 cases

Encapsulated papillary oncocytic neoplasms (EPONs) of the thyroid are rare tumors, whose relationship to other thyroid tumors has not been thoroughly elucidated. Earlier, they have been regarded as variants of papillary thyroid carcinoma (PTC), hyperplastic lesions, and follicular neoplasms. Eighteen EPONs were retrieved from our surgical pathology files and reviewed for defining morphologic features. Cases having the typical nuclear features of PTC were excluded. Immunohistochemistry (IHC) for CK19, HBME1, and CD56 was carried out. Microdissection, polymerase chain reaction, and sequencing of exon 15 of the BRAF gene were completed. Cases were evaluated for rearranged in transformation/papillary thyroid carcinoma RET/PTC rearrangement by fluorescent in situ hybridization (FISH). The majority of the tumors exhibited a distinctive histologic appearance. They were composed of true papillae lined by a single layer of predominantly cuboidal cells with oncocytic cytoplasm; hobnailing was typically prominent. Three tumors showed taller cells with uniformly apical nuclei and no hobnailing. Ten of 18 cases showed vascular and/or capsular invasion; hence, if the diagnostic criteria used to evaluate follicular neoplasms are applied, more than half of the tumors would be considered minimally invasive carcinomas. No cases were immunoreactive with antibodies to HBME1, whereas only 1 of 13 was immunoreactive for CK19. Six of 7 interpretable cases were immunoreactive for CD56. No BRAF point mutations or RET/PTC rearrangements were identified in the examined cases. All patients were alive at the time of last follow-up and no locally recurrent disease had been reported; however, 1 case was remarkable for a lymph node metastasis. Our results confirm that EPONs are histologically, immunohistochemically, and molecularly distinct from papillary thyroid carcinoma and seem to be most related to follicular neoplasms.     

Differential expression of galectin-3 in papillary projections of malignant and non-malignant hyperplastic thyroid lesions

Galectin-3 is a a beta-galactoside binding protein recently proposed to be a promising presurgical molecular marker for distinguishing benign from malignant thyroid neoplasms. We analyzed galectin-3 expression immunohistochemically in papillary areas of hyperplastic lesions of benign thyroid tissue in comparison with malignant papillary projections of papillary thyroid carcinoma (PTC). A monoclonal antibody to galectin-3 and ABC immunohistochemical technique were used to evaluate galectin-3 expression in 26 cases of benign papillary hyperplasia (8 cases of hyperplastic adenoma, 8 cases of hyperplastic colloid goiter, 10 cases of Graves disease) in comparison with 25 cases of PTC. Immunohistochemical results showed no reactivity for galectin-3 in papillary areas of benign hyperplastic lesions. Strong cytoplasmic galectin-3 immunoreactivity was found in all 25 cases of PTC. These results show that galectin-3 expression is a feature of malignant papillary projections but not of benign papillary hyperplasia. Thus, the immunohistochemical evaluation of galectin-3 might contribute to differential diagnosis between malignant and benign thyroid lesions with papillary projections.     

Thyroid carcinoma in patients with familial adenomatous polyposis

There has been a growing awareness of the association between papillary thyroid carcinoma and familial adenomatous polyposis (FAP). The cases of four young patients with papillary thyroid carcinoma occurring with FAP are presented. Three patients underwent surgery to provide specimens for detailed histological examination. The surgical specimens showed well-encapsulated multicentric tumours exhibiting a predominantly papillary architectural growth pattern. In some areas, follicular architecture and cribriform patterns were noted. Atypical areas of spindle cells in a trabecular or solid configuration, which are not normally seen in classical papillary thyroid carcinoma, were evident. Malignant cells exhibited a graduation of cuboidal to tall cells with abundant amphophilic cytoplasm. The nuclei did not exhibit the typical nuclear clearing as seen in papillary thyroid carcinoma, but nuclear grooving and inclusions were noted. Psammoma bodies were not seen in any of the specimens. In a limited review of these patients, features such as young age at presentation, multicentricity and unusual histology suggest that thyroid carcinoma associated with FAP may represent a distinct form of thyroid cancer.     

Thyroid disorders. Part III: neoplastic thyroid disease.

This paper is part III of the series on thyroid disorders. Thyroid tumors are the most common endocrine neoplasms. Most of these tumors are benign hyperplastic or colloid nodules or benign follicular adenomas. However, 5% to 10% of the lesions that come to medical attention are carcinomas. A major clinical challenge is establishing which nodules are hyperplastic, benign, or malignant. History, clinical findings, ultrasonography, and fine-needle aspiration biopsy are the mainstays for diagnosis. There are 3 main histologic types of thyroid cancer: differentiated, medullary, and anaplastic. Differentiated lesions are subdivided into papillary, follicular, and Hurthle cell carcinomas. In addition, primary lymphoma may occur in the thyroid gland and other cancers may metastasize to the thyroid. An important neoplastic syndrome, multiple endocrine neoplasia type 2 (MEN2), involves medullary carcinoma of the thyroid gland. In 2002 there were 10 cases of thyroid cancer per 100 000 population. During the past 10 years the rate of thyroid cancer has been increasing 5% per year. The overall 10-year survival for papillary carcinoma is 80% to 90%, follicular carcinoma 65% to 75%, and medullary carcinoma 60% to 70%. The prognosis for anaplastic carcinoma is very poor and 5-year survival is rare. The dentist by inspection and palpation of the neck in the area of the thyroid gland may detect single or multiple lesions that may be benign or malignant. Patients with identified nodules or enlarged thyroid glands should be referred for diagnosis and treatment. Patients with thyroid cancer will benefit from the early detection and treatment of their lesions as early detection can lead to a cure or prolongation of their life.     

Insular carcinoma of the thyroid in a 10-year-old child

Thyroid carcinomas are relatively infrequent in the pediatric age group, the majority of which are papillary carcinomas. Poorly differentiated carcinomas are very rare in this age group. Insular carcinoma is a unique subset of poorly differentiated carcinoma of thyroid, which occurs predominantly in adults older than 50 years. In terms of prognosis, insular carcinoma of thyroid occupies a place in between that of well-differentiated papillary/follicular carcinoma and anaplastic carcinoma. The authors describe a case of insular carcinoma of thyroid in a 10-year-old girl who underwent hemithyroidectomy based on a preoperative diagnosis (by fine-needle aspiration cytology) of colloid goiter, and after histopathologic diagnosis of the specimen, a completion thyroidectomy was performed with block dissection of the neck. The authors believe this to be the youngest case of insular carcinoma of thyroid to be reported.     

Application of staging systems for differentiated thyroid carcinoma in an endemic goiter region with iodine substitution

OBJECTIVE: To evaluate and compare staging systems for differentiated thyroid carcinoma and predicted outcome in an endemic goiter region with iodine substitution and to examine the risk profile of differentiated thyroid carcinoma and compare it against nongoiter regions. SUMMARY BACKGROUND DATA: Differentiated (papillary or follicular) thyroid carcinoma has a favorable prognostic outcome. In numerous studies prognostic factors have been identified and staging systems created, particularly in Anglo-American centers (nonendemic goiter regions), to evaluate individual prognostic outcome. METHODS: In a retrospective study, the authors assessed 440 patients with differentiated thyroid carcinoma (papillary, n = 293; follicular, n = 147) and a long-term follow-up of median 10.6 years to determine the predictive accuracy of nine staging systems applicable to the study population; the systems were compared by calculating the proportion of variation explained. RESULTS: With regard to cause-specific mortality, the difference between the respective stages and/or risk groups was highly significant for every staging system. By means of calculating the proportion of variation explained, MACIS scoring supplied the most reliable prognostic information for differentiated thyroid carcinoma (relative importance 16.93%). EORTC and UICC/AJCC systems had a relative importance of 16.34% and 13.96%, respectively, also a high level of accuracy; this implies that they are superior to the other six staging systems. If we separate papillary and follicular carcinoma, for the former the MACIS score with a relative importance of 15.05% is clearly superior to the other staging systems, whereas for the latter the EORTC score and the UICC/AJCC staging system, with relative importance of 17.04% and 16.58%, respectively, yield the best prognostic information. CONCLUSIONS: By applying staging systems in an endemic goiter region with iodine substitution, the best prognostic information for papillary thyroid carcinoma has been achieved with the MACIS score, while for follicular thyroid carcinoma the EORTC score and the UICC/AJCC system have the best prognostic accuracy. Because of the individual factors, which are easy to obtain and generally available (age, T, N, M classification), the uncomplicated handling, and the widespread use and the good predictive accuracy, the UICC/AJCC classification is the staging system of choice for comparing published results.     

Incidental carcinoma in thyroid pathology: our experience and review of the literature

The diagnosis of incidental thyroid carcinoma in patients submitted to thyroidectomy for a benign disease is quite frequent. A retrospective analysis was performed on 240 patients submitted to surgical intervention in order to establish the incidence of the carcinoma. One hundred sixty five patients (68.75%) were affected by benign disease (132 multinodular goiter, 30 uninodular goiter, 2 Plummer and 1 Basedow) and 75 (31.25%) by carcinoma. In 30 of 165 patients (18.2 %), affected by benign disease, occurred a histological diagnosis of thyroid carcinoma, (18 papillary carcinoma, 6 follicular carcinoma, 5 papillary carcinoma follicular variant and 1 oncocytic carcinoma). In this study it's considered incidental thyroid carcinoma the one occurred in patients who never underwent FNA and there were no suspicious features in all exams that may suggest the presence of carcinoma. Fifteen of the 30 incidental carcinoma (50%) were microcarcinomas; in the other 13, dimensions were more than 1 cm, but less than 2 cm in 9 cases. Two patients had a synchronous carcinoma. Actually these patients are still in a follow up program and no recurrency of disease is occasionally observed. This study shows that the only way to put doubts on the real benignity of the disease is the fine needle aspiration; there are no other instruments that could let think about the occurrence of the carcinoma. Moreover in the majority of cases the incidental carcinoma is a microcarcinoma, it doesn't reach significant volume, may be not centered by a FNAB, but in must cases it's not really biologically aggressive.     

Fat-containing lesions of the thyroid gland

Thyroid lesions containing adipose tissue are rare; only scattered case reports are recorded. This study of 17 lipomatous thyroid lesions on file at the Armed Forces Institute of Pathology was undertaken to better document the full range of these abnormalities. Patient ages ranged from 11 to 75 years; nine patients were female and eight were male. Fat-containing thyroid neoplasms included seven papillary carcinomas, four adenomatoid nodules, one follicular adenoma, and one minimally invasive follicular carcinoma. Nonneoplastic conditions associated with adipose tissue included four cases of amyloid goiter, two cases of lymphocytic thyroiditis, one case of dyshormonogenetic goiter, and one case of thyroid atrophy. This study documents the presence of adipose tissue in a wider range of benign and malignant thyroid lesions than has previously been reported.     

Observer variation of encapsulated follicular lesions of the thyroid gland

Although histologic definition of follicular thyroid lesions is readily available, application of the diagnostic criteria and personal experience may lead to disagreement among pathologists. To investigate interobserver variation in assessment of encapsulated follicular lesions, eight pathologists (four American and four Japanese) reviewed the same hematoxylin and eosin-stained slide of each of 21 cases of thyroid lesions showing encapsulation and follicular growth pattern. In 10% of the cases, there was complete agreement. At least seven pathologists agreed on the diagnosis in 29% of the cases, and at least six in 76% of the cases. American and Japanese pathologists agreed among themselves in 33% and 52% of cases, respectively. The frequency of diagnosis of adenomatous goiter among Japanese pathologists (31%) was considerably higher than that among American pathologists (6%). In contrast, the frequency of diagnosis (25%) of papillary carcinoma among American pathologists was considerably higher than that (4%) among Japanese pathologists. Our analysis revealed three main factors affecting observer variation: 1) interpretation of the significance of microfollicles intimately related to capillaries within the tumor capsule, 2) evaluation of what constituted the type of nuclear clearing indicative of papillary carcinoma, and 3) absence of clear morphologic criteria for separation of adenomatous goiter and follicular adenoma. To reduce observer variation of encapsulated follicular lesions, it will be necessary to provide more explicit criteria for diagnosis.     

Unifocal autonomy and carcinoma of the thyroid gland]

Two cases operated upon with the clinical diagnosis of unifocal autonomous functioning thyroid nodules (AFTN) are reported where the histological diagnosis revealed a well differentiated thyroid carcinoma (follicular, papillary) without metastasis. The pathogenesis of differentiated thyroid carcinomas in cases of AFTN may be coincident. Alternatively it may evolve from thyroid epithelial cells of the hot nodule, resulting in a "hot" well differentiated thyroid carcinoma. These cases show that under the clinical diagnosis of AFTN a differentiated thyroid carcinoma can be hidden occasionally.     

Follicular variant of thyroid papillary carcinoma: a clinicopathologic study of six cases

The clinicopathologic features of six cases of a peculiar variant of differentiated carcinoma of the thyroid composed of follicles with or without solid areas and having a characteristics ground-glass appearance of the nuclei were studied and compared with those of conventional papillary and follicular carcinomas. This variant resembled papillary carcinoma in its biologic behavior and all morphologic features with the exception that papillae were not present. The term "papillary carcinoma, follicular variant" is proposed for this tumor type in order to emphasize its close biologic relationship with the conventional papillary carcinoma.     

Fine needle aspiration biopsy of thyroid nodules

The clinical value of the fine needle aspiration of thyroid nodules was evaluated by comparing preoperative cytology to subsequent pathology in 109 patients undergoing thyroidectomy. Preoperative cytology was reported as insufficient cellular material (31 patients), benign goiter (27 patients), follicular neoplasm (22 patients), thyroiditis (12 patients), suspicious for papillary carcinoma (nine patients), Hurthle cell neoplasm (five patients), medullary carcinoma (one patient), lymphoma (one patient), and metastatic adenocarcinoma (one patient). Operative findings demonstrated that the overall sensitivity of fine needle aspiration in diagnosing thyroid neoplasia (carcinoma or adenoma) was 88% and its specificity was 80%. Operation verified the cytologic diagnosis of medullary carcinoma, lymphoma, metastatic adenocarcinoma, and seven of nine papillary carcinomas. Of the five patients with an aspiration biopsy diagnosis of Hurthle cell neoplasm, three patients had carcinoma and one had an adenoma. Four carcinomas and 12 follicular adenomas were found in patients with a cytologic diagnosis of follicular neoplasm. Thyroiditis was confirmed at operation in all 12 patients with this diagnosis on fine needle aspiration. One carcinoma was found in the 27 patients with benign goiter diagnosed on cytology. Fine needle aspiration is a valuable tool that can lead to earlier diagnosis and treatment of thyroid cancer. However, a negative aspiration does not supplant good clinical judgement in determining the need for thyroidectomy.     

MET receptor tyrosine kinase sequence alterations in differentiated thyroid carcinoma

Activating mutations affecting the MET receptor tyrosine kinase are present in several types of human cancer, particularly in papillary renal cell carcinoma. Papillary thyroid carcinomas commonly express high levels of MET mRNA and protein, suggesting that increased MET signaling may be of importance in the molecular pathogenesis of differentiated thyroid carcinoma. To evaluate the role of MET mutations in thyroid carcinoma, we screened MET exons 2 to 21 for mutations in sporadic papillary, follicular, medullary, and anaplastic thyroid carcinomas using denaturing high-performance chromatography. A missense MET sequence alteration T1010I, located in exon 14 encoding for the juxtamembrane domain of MET, was found in 6 (6%) of the 104 thyroid carcinomas examined, whereas all 92 goiter samples had wild-type exon 14 (P = 0.031). Three (6%) of the 53 papillary, 2 (10%) of the 21 follicular, 1 (8%) of the 13 medullary, and none of the 17 anaplastic carcinomas studied had MET(T1010I). Four of the 6 T1010I sequence alterations were present also in the germline. MET protein expression showed no apparent association with the presence of MET(T1010I), and the clinical features of the patients with cancer with MET(T1010I) were similar to those of patients whose cancer did not harbor MET(T1010I). We conclude that MET(T1010I) sequence alteration is relatively frequent in differentiated thyroid carcinoma. The clinical and the molecular pathologic significance of this MET sequence alteration is not known.